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Unexpected lessons learned this flu season

New influenza strain reminds the public that influenza is not harmless while making health officials aware of the vaccine program's shortcomings.

March 01, 2004|Jane E. Allen | Times Staff Writer

When otherwise healthy children began dying of the flu late last fall, adults nationwide made a sudden, mad scramble for the often-ignored influenza vaccine. Lines formed at clinics, reports of an unexpected flu strain fueled fears of a pandemic and accusations swirled about the immunization's effectiveness.

Only a few weeks later, the number of cases had dropped to more typical levels. So too had public interest.

As it turns out, the 2003-04 flu season appears to have been no worse than many other seasons. Even though it peaked extremely early -- in December -- the numbers of people who became sick or died weren't unusual.

The season did have an impact, however. As health officials prepare for a new season, they're paying special attention to the last season's legacy -- both in public awareness and in their strategies to deal with new outbreaks.

The highly publicized deaths of dozens of children -- first in Colorado, later in other states -- finally jolted many Americans out of their complacency about flu. In Los Angeles County alone, the number of people calling a county health department hotline in search of the vaccine quadrupled, said Dr. David E. Dassey, the county's deputy chief of acute communicable disease control.

Far from just another winter nuisance, influenza viruses are deadly. They typically kill 36,000 people every year, 90% of them elderly, and hospitalize 114,000. This year's childhood deaths and hospitalizations "put a face on what was up to that point just numbers and statistics," said Dr. Walter Orenstein, outgoing director of the National Immunization Program at the federal Centers for Disease Control and Prevention in Atlanta.

At last week's meeting of the Federal Advisory Committee on Immunization Practices, the CDC reported that at least 135 children under age 18 died of the flu this season. (The death toll could be higher because there's no requirement that flu cases be reported.) The number is in line with CDC estimates that about 92 children under the age of 5 will die each year from the flu, but it remains unclear whether children were more severely affected than in most years.

The public panic stemmed from more than just news reports of children's deaths, though. The specter of anthrax and SARS hung in the air.

"There's still a memory out there among the medical community from two years ago, where we were asking them to be on alert for possible bioterrorism, then starting last winter, SARS, and ... suddenly there's this panic about flu," Dassey said.

Although the flu never became a pandemic, the spread of a new flu strain and the resulting worry forced federal health agencies to acknowledge their inability to respond quickly to changing vaccine strains and sudden surges in demand. Eventually, the country must improve disease surveillance and create a vaccine stockpile, Orenstein said.

The public's unexpected, and in some cases unmet, demand for the vaccine highlighted weaknesses in vaccine production. Manufacturers still rely upon millions of chicken eggs to create the vaccine -- a time-consuming, delicate process. At a time when avian flu is sweeping Asian poultry flocks, that process is particularly in danger of going awry. If avian flu were to infect U.S. poultry, it could cripple vaccine makers' ability to produce enough doses.

The threat of a virulent flu strain also added impetus to CDC discussions of a universal vaccine recommendation. During last week's advisory committee meeting, the CDC said a subcommittee would begin studying whether it's feasible to vaccinate every American, except babies younger than 6 months and people with severe allergies to eggs or other vaccine components.

If everyone were advised to get the vaccine, health experts say, more people would treat the flu as a threat and seek the vaccine -- thereby making it easier to determine how many doses need to be produced and making public health agencies better-prepared for a pandemic.

Currently, the CDC recommends that 185 million Americans including children over age 2, adults older than 50, those with chronic conditions or compromised immune systems and healthcare workers be vaccinated. But because so few people generally take the vaccine, manufacturers made just 87 million doses this year, based on a calculation that took into account the millions of unused doses they've destroyed in past years.

The time required to prepare the vaccine is always problematic, with researchers forced to make predictions in the spring about what flu strains will be prevalent months later.

The predominant strain of influenza this winter was the A-Fujian strain. Although it was identified in January 2003, federal officials last spring chose a vaccine formula that didn't include it. They've since defended their actions, saying they weren't confident they could have had a new vaccine ready in time for the new season.

Even as the problems in flu immunization campaigns become clearer, federal officials already are planning next winter's vaccine. An FDA advisory committee last month preliminarily approved a 2004-05 vaccine. It includes this year's predominant A-Fujian strain, a new type-B strain and the A-Caledonia strain. A final decision is expected mid-month. However, the emergence of another new strain or the crossover of avian flu to humans could render it nearly useless.

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